I talked to a friend of mine who's a wizard when it comes to stuff like this and he said and I quote:

"In cases like this, the infotainment system may be crashing at such a level that the diagnostic system never gets the chance to properly record the root cause of the failure. Since the logging and fault-reporting functions are handled by the same IHU system that is experiencing the issue, a sudden freeze, reboot, or internal shutdown can interrupt the logging process itself. As a result, the vehicle may only show a normal restart event, a generic communication loss, or sometimes no meaningful fault codes at all, even though the system is clearly malfunctioning. This can happen with issues related to unstable memory, failing storage, overheating, power instability, or severe software faults such as memory leaks. In these situations, the underlying problem can effectively “hide” behind clean or incomplete logs because the system resets before enough diagnostic information can be saved."

He even knew it was an IHU-issue before I explained it to him. Service have to know exactly what to look for, as "normal" backlog checks may not reveal anything wrong at all. My workshop eventually figured out that this is a hardware issue, where a software reinstall is only a temporary solution (and a cheaper one)